This invention relates to knowledge based information retrieval system and in particular to a human interface of an intellectual query system permitting the end user to query efficiently information stored in a network structure in an electronic file.
This interface can be divided into the natural language interface and the visual interface. The natural language interface is suitable for a global search, by which the search is effected by deduction from the natural language and the visual interface is suitable for a search from a domain, which can be seen by eyes, i.e. for a local search.
Heretofore, as a human interface using the natural language, there is known a natural language interface for the database. Therefor there are references, G. G. Hendrix et al., "Developing a Natural Language Interface to Complex Data", ACM Trans. Database Systems, Vol. 3, 1978, pp. 105-147, etc. In these systems a data model for the database (method, by which the relation between different data items, which are to be memorized, is expressed) and a grammar and a dictionary for interpreting the natural language are set independently. That is, when the natural language interface is added to an existing database, it is necessary to construct newly a grammar and a dictionary. Or it has a problematical point that it is necessary to modify the grammar and the dictionary for the natural language interface, when the object database is changed.
Further, heretofore, a database, to which the natural language interface is given, is a relational database and the formal language for the search used therefor, i.e. a quasi-standardized SQL (Structural Query Language), is weak in the capability for describing high order knowledge. Since a query expression by the natural language is translated usually into a formal language as such an intermediate language, it has a problematical point that the function of the whole system is restricted by the expressing capacity of this formal language. In particular, although the relational database is useful for uniform data, it cannot be said that it is satisfactorily suitable for a heterogeneous database, by which various kinds of matters are dealt with, or an object-oriented database. For example, it is not suitable for describing a matter, based on ambiguous memory of a user, and querying information concerning it, based on that description.
Further, in these systems means other than the natural language is used for inputting data (new knowledge and information) and the data input is carried out by a specialist. Consequently there is a problem that it is difficult for an end user to input and register directly the data.
Furthermore, as small scale and large capacity memory devices such as optical disk storage units have been realized, document filing devices directed to offices, for which the end user operates directly the processing of supervision and search of the database, capable of storing and querying a large amount of information, which has been effected heretofore by a specialist, have been realized.
As a method for facilitating memory and search of information in such a filing device, e.g. JP-A-61-220027 can be referred to. This literature discloses an information querying method enabling the end user to query easily desired documents etc. from ambiguous and fragmental information and at the same time to facilitate their registration. However, by this method, it is very difficult to form query conditions, under which information required by the user can be appropriately taken out, when the query conditions for effecting the query from the knowledge base are formed.